Authorities say a passing driver who stopped to investigate a damaged tree in southwest Washington found two young Astoria girls injured in a car crash that killed their mother.

The Washington State Patrol estimates the car driven by 26-year-old Jessica Marie Rath of Astoria, Ore., hit the tree sometime early Wednesday morning.

The crashed vehicle wasn't visible from State Highway 401 south of Naselle. State Police say it appears Rath fell asleep at the wheel.

Trooper Russ Winger said it's likely the 4-year-old girl pulled her more seriously injured 2-year-old sister from the car and covered both of them with a blanket. The overnight temperature was in the low 40s. Winger said the girls could have easily died if they had been out there for any longer

The girls were taken first to Columbia Memorial Hospital, where their father met them. Both children were later transfered to OHSU in Portland for further care. The trooper says the mother had driven Tuesday night to the Hoquiam, Wash., area to pick up her fisherman husband but then headed south when she found out her husband's boat was headed elsewhere.